Emergency vehicle cots (also known as ambulance cots) are specialized stretchers usually used in association with emergency vehicles. The ambulance cot is deemed to be specialized due to it being capable of easy loading into the emergency vehicle, namely, the wheeled base and support structure are collapsible as the cot is moved into the inside of the emergency vehicle to facilitate ambulance personnel to work on the patient lying on the cot in the fairly limited space inside the emergency vehicle. Although preexisting ambulance cots have been generally adequate for their intended purposes, they have not been satisfactory in all respects.
One exception to the aforesaid statement is the emergency vehicle cot disclosed in pending application Ser. No. 09/102 143, filed on Jun. 22, 1999, assigned to the same assignee as is the present application. This emergency vehicle cot, however, requires the synchronized operation of a lifting procedure and an operation of the handles located at opposite ends of the cot by the emergency personnel in order to effect a vertical adjustment of the elevation of the patient supporting surface between the "load position" and positions oriented therebelow. Oftentimes, and in emergency situations, the two emergency personnel do not always lift and operate the handles in synchronization and, as a result, the mechanism automatically resets and it becomes awkward and time consuming to effect a new operation to effect a movement of the patient supporting surface to levels oriented between the "load position" and the lowestmost or folded position. As is explained in the aforesaid pending application, if the attempt to adjust the vertical height of the patient supporting surface is attempted with both emergency personnel not being synchronized in their lifting and handle operation technique, the emergency personnel's operation of the handle at the foot end of the cot without the simultaneous operation of the other handle by the emergency personnel at the head end of the cot will cause, when the handle at the foot end is released, a safety control mechanism to rest to prevent any single handle from enabling the level of the patient supporting surface to be altered. Thus, it is desirable for there to be provided a mechanism which assures the emergency personnel that an altering of the height of the patient supporting surface can effectively take place only when both ends of the cot are sufficiently supported so as to not jeopardize the safety of the patient supported on the patient supporting surface.
Accordingly, it is an object of the present invention to provide an ambulance cot with an improved support mechanism with a safety mechanism which prevents a release of the locking mechanism for the vertical height adjustment unless both ends of the emergency cot are lifted and, therefore, supported by emergency personnel. A control mechanism is purposefully moved to the activated state to enable the emergency personnel to lift while one of them sets the safety mechanism for release and thereafter both of them initiate a safe and controlled raising or lowering of the patient supporting surface.
It is a further object of the invention to provide a control mechanism on the ambulance cot, as aforesaid, for preventing inadvertent collapsing of the support mechanism when the support mechanism is in its highest most position, known in the field as the "load position".
It is a further object of the invention to provide an ambulance cot, as aforesaid, and a control mechanism, as aforesaid, which must be activated to enable the support mechanism to be released from its "load position" to allow the base to collapse toward the patient litter support to enable insertion of the ambulance cot easily into the emergency vehicle.
It is a further object of the invention to provide a control mechanism, as aforesaid, which is movable between activated and inactive states only when the ambulance cot is in the load position and which, in the activated state, permits a load process to begin by manual operation of only one handle, and which automatically resets to an inactive state upon a manual operation of the handle so that an abort of the load process caused by a release of the handle will always necessitate a reactivation of the control mechanism to enable the support mechanism to be released from its load position to allow the base to collapse toward the patient litter support mechanism to enable insertion of the now fully folded ambulance cot easily into the emergency vehicle.
It is a further object of the invention to provide a control mechanism, as aforesaid, which, when moved to an activated state, permits a lowering of the ambulance cot from the load position to positions below the load position only in response to a lifting of both ends of a sufficient amount to reduce a majority of the load on the wheels and a simultaneous manual operation of one handle of the release mechanism oriented at one of the ends of the ambulance cot.
It is a further object of the invention to provide an ambulance cot, as aforesaid, wherein the control mechanism requires the attendance of two emergency personnel in order to effect movements of the support mechanism and the patient litter support thereon to positions intermediate the load position and the folded position.